In many applications, especially those involving electronics, patterned coatings must be formed in one or more layers on a substrate. Available pattern formation methods include masking the substrate with tape and photoimaging. In masking, a tape is applied in a pattern over parts of the substrate. After coating the substrate using any convenient method (e.g., spin coating) and drying or curing the coating, the tape can be manually removed, leaving the patterned coating. However, coating build-up or edge distortion sometimes occurs near the pattern boundaries, and applying and removing the tape can be tedious. In photoimaging, a photocurable polymer is applied to the substrate, imaged in a pattern (using, for example a partially transparent and partially occluded mask and UV or shorter wavelength light), then removed from the unimaged areas (in a step sometimes called “lift-off”) using a suitable solvent. The choice of suitable photoimaging resins may be somewhat limited because many removal solvents may adversely affect the photocured polymer coating. The removal solvent may also pose environmental and other hazards.
References describing patterned coating or printed circuit formation include U.S. Pat. Nos. 3,931,454, 5,121,134, 5,145,717 5,165,962, 5,658,469, 5,759,625, 6,300,042 B1, 6,329,227 B2, 6,498,114 B1 and 6,559,474 B1. U.S. Pat. No. 5,468,324 describes a method for data recording duplication and microstructure fabrication. U.S. Pat. No. 6,352,758 B1 describes a patterned article. References involving masking include U.S. Pat. Nos. 5,104,711 and 5,165,962.